Vertebral body replacement

ABSTRACT

The present invention involves a system and methods for assembling and implanting a vertebral body implant. The vertebral body implant includes, but is not necessarily limited to, an expandable core body and endplates that can be attached at both ends. Endplates of various shapes, sizes and angles are attachable to the expandable core so that a suitable vertebral body implant can be implanted between vertebrae.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/964,836 filed on Aug. 12, 2013, which is a continuation of U.S.patent application Ser. No. 12/661,206 filed on Mar. 12, 2010, which isa non-provisional patent application and claims the benefit of priorityfrom commonly owned and U.S. Provisional Patent Application Ser. Nos.61/159,792 filed on Mar. 12, 2009, and 61/260,375 filed on Nov. 11,2009. The entire contents of these previous related applications areeach hereby expressly incorporated by reference into this disclosure.

FIELD

The present application relates generally to spinal implants and methodsfor replacing at least a portion of one or more vertebral bodies of aspine.

BACKGROUND

The spine is formed of a column of vertebra that extends between thecranium and pelvis. The three major sections of the spine are known asthe cervical, thoracic and lumbar regions. There are 7 cervicalvertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae, with each ofthe 24 vertebrae being separated from each other by an intervertebraldisc. A series of about 9 fused vertebrae extend from the lumbar regionof the spine and make up the pelvic region of the vertebral column.These fused vertebrae consist of the sacral and coccygeal region of thevertebral column.

The main functions of the spine are to provide skeletal support andprotect the spinal cord. Even slight disruptions to either theintervertebral discs or vertebrae can result in serious discomfort dueto compression of nerve fibers either within the spinal cord orextending from the spinal cord. If a disruption to the spine becomessevere enough, damage to a nerve or part of the spinal cord may occurand can result in partial to total loss of bodily functions (e.g.walking, talking, and breathing). Therefore, it is of great interest andconcern to be able to both correct and prevent any ailments of thespine.

Trauma to the spine (e.g. car accident, sports injury) can causefracturing of one or more vertebrae. Certain diseases affecting thespine (e.g. tumors, osteoporosis) can cause degeneration of the spine.Both trauma and degeneration may result in severe disruption to thespine. In these circumstances, the complete removal of one or morevertebrae may be required. If one or more vertebrae are removed, areplacement support system must be implanted in order to protect thespinal cord and maintain, or improve, the structure and integrity of thespine.

The present invention is directed at overcoming, or at least improvingupon, disadvantages of the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one example of a vertebral body implantassembly, according to one embodiment of the present invention;

FIG. 2 is a perspective view of an outer tubular core forming part ofthe implant assembly of FIG. 1;

FIG. 3 is an exploded view of the core expanding body forming part ofthe implant assembly of FIG. 1;

FIG. 4 is a partially exploded view directed at illustrating the guidepin and guide track interaction of the implant assembly of FIG. 1;

FIG. 5 is a perspective view of the adjustment ring forming part of theimplant assembly of FIG. 1;

FIG. 6 is a cross section view of the adjustment ring of FIG. 5 takenalong line 6-6 of FIG. 5;

FIG. 7 is a perspective view of the core expanding body forming part ofthe implant assembly of FIG. 1;

FIG. 8A is a cross section view of the core expanding body of FIG. 7taken along line 8-8 of FIG. 7;

FIG. 8B is a cross section view of the adjustment ring and outer tubularcore of the core expanding body of FIG. 7 taken along line 8-8 of FIG.7;

FIG. 9 is a perspective view of the inner tubular core forming part ofthe implant assembly of FIG. 1;

FIG. 10 is a top perspective view of one example of an endplate formingpart of the implant assembly of FIG. 1;

FIG. 11 is a top view of the endplate of FIG. 11;

FIG. 12A is a cross section view of the endplate of FIG. 11 taken alongline 12-12 of FIG. 11;

FIG. 12B is a cross section view of the endplate and inner tubular coreof the implant assembly of FIG. 1;

FIG. 12C is a cross section view of the endplate and outer tubular coreof the implant assembly of FIG. 1;

FIG. 13 is a bottom perspective view of the endplate of FIG. 10;

FIG. 14 is a bottom view of a second example of an endplate forming partof the implant assembly of FIG. 1;

FIG. 15 is a bottom view of a third example of an endplate forming partof the implant assembly of FIG. 1;

FIG. 16 is a bottom view of a fourth example of an endplate forming partof the implant assembly of FIG. 1;

FIG. 17 is a bottom view of a fifth example of an endplate forming partof the implant assembly of FIG. 1;

FIG. 18 is a side view of the endplate of FIG. 16;

FIG. 19 is a perspective view of a vertebral body implant assemblyaccording to a another embodiment of the present invention;

FIG. 20 is a perspective view of an extension piece forming part of theimplant assembly of FIG. 22;

FIG. 21 is a cross section view of the extension piece of FIG. 20 takenalong line 21-21 of FIG. 23;

FIG. 22 is a top view of one example of a combined insertion andexpansion tool, according to one embodiment of the present invention;

FIG. 23 is a side view of the expanding tool of FIG. 22;

FIGS. 24A-B are a cross section view of the expanding tool of FIG. 23taken along line 24-24 of FIG. 23;

FIG. 25 is a cross section view of the expanding tool of FIG. 23 takenalong line 25-25 of FIG. 23;

FIG. 26 is a partial view of the expanding tool taken from partial viewarea 26 of FIG. 25;

FIG. 27 is a partial view of the expanding tool taken from partial viewarea 27 of FIG. 24;

FIG. 28 is a partial view of the expanding tool taken from partial viewarea 28 of FIG. 27;

FIG. 29 is a partial view of the expanding tool taken from partial viewarea 29 of FIG. 24;

FIG. 30 is a side perspective view of the core expanding body of FIG. 7coupled with the expanding tool of FIG. 25, according to one embodimentof the present invention;

FIG. 31 is a perspective cross section view of the expanding bodycoupled with the expanding tool of FIG. 30 taken along line 31-31 ofFIG. 30;

FIG. 32 is a top view of the loading block, according to one embodimentof the present invention;

FIG. 33 is a side view of the loading block of FIG. 32;

FIG. 34 is a perspective view of a vertebral body implant assemblyaccording to a another embodiment of the present invention;

FIG. 35 is a perspective view of a first side of an endplate accordingto the embodiment of FIG. 34;

FIG. 36 is a perspective view of a second side of an endplate accordingto the embodiment of FIG. 34;

FIG. 37 is a perspective view of a lock screw for releasably fixing theendplate of FIGS. 35 and 36 to the core of the implant of FIG. 34;

FIG. 38 is an exploded perspective view of the implant of the implant ofFIG. 34;

FIG. 39 is a perspective cross section of the implant of FIG. 34;

FIG. 40 is a side view of one example of an expansion tool for insertingand expanding the implant of FIG. 34;

FIG. 41 is a cross section view of the distal end of the expansion toolof FIG. 40;

FIG. 42 is a side view of the distal end of the expansion tool of FIG.41 with the outer housing and outer tube removed for the purposes ofillustration; and

FIG. 43A-43E is a series of side views of the implant assembly of FIG. 1engaged with the expanding tool of FIG. 23 and the process of implantingthe expandable vertebral body between a first vertebra and secondvertebra.

DETAILED DESCRIPTION OF AN EXAMPLE EMBODIMENT

Illustrative embodiments of the invention are described below. In theinterest of clarity, not all features of an actual implementation aredescribed in this specification. It will of course be appreciated thatin the development of any such actual embodiment, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as a compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure. The expandable vertebral body replacement disclosedherein boasts a variety of inventive features and components thatwarrant patent protection, both individually and in combination.

FIG. 1 illustrates an example of a vertebral body implant assembly 10according to a first embodiment of the present invention. The vertebralbody implant assembly 10 includes endplates 11 fixed at the superior andinferior ends of a tubular core expanding body 12 wherein the expandableimplant can be customized to accommodate various needs by attaching froma selection of different endplates. The customization of the expandabletubular core can be done moments before implant of the expandablevertebral body replacement, which gives the benefit of customizing theimplant based on expected and unexpected circumstances and conditions ofthe surrounding vertebral bodies.

The core expanding body 12 includes an adjustment ring 13, an outertubular core 14, an inner tubular core 15, one or more guide pins 20,and one or more set screws 16. As will be explained in greater detailbelow, the vertebral body implant assembly 10 of the present inventionmay be inserted into a space left by the removal of at least part of oneor more vertebra in order to maintain a desired spacing between theremaining vertebrae and to stabilize the affected spinal segments. To doso, the vertebral body implant assembly 10 is placed, preferably in acollapsed state, in the space between the remaining superior andinferior vertebral bodies. Rotation of the adjustment ring 13, which isfixed at one end of the outer tubular core 14 of the core expanding body12, results in the expansion of the core expanding body 12 due to theouter tubular core 14 and inner tubular core 15 moving in oppositedirections along their central axis. Expansion of the core expandingbody 12 may be continued until the desired spacing between the vertebralbodies is achieved. Once the desired spacing is reached, a set screw 16in the wall of the outer tubular core 14 is engaged into the exteriorthreads 31 of the inner tubular core 15 to secure the expanded positionof the vertebral body implant assembly 10 and prevent further heightalterations of the vertebral body implant assembly 10.

Referring to FIGS. 2-9, the outer tubular core 14 includes indentedslots 23, a plurality of holes 38, an opening 24, a first end 39, asecond end 41, a plurality of flanges 25 with a distal step 26 forming agroove 44, and an endplate attachment feature 22. Indented slots 23 onthe exterior wall of the outer tubular core 14 allow for theanti-rotational attachment of the expanding tool, described below. Theplurality of holes 38 in the wall of the outer tubular core 14 allow thetransport of blood and nutrients through the core expanding body 12 onceimplanted, which assists in new bone growth between the remainingvertebra. The relatively large opening 24 in the side of the outertubular core 14 allows the placement of additional bone growth promotingmaterial to be added once the vertebral body implant assembly 10 hasbeen positioned in the body and expanded to a desired height. Aplurality of flanges 25 with a distal step 26 extend from the first end39 of the outer tubular core 14 and function to secure the attachment ofthe adjustment ring 13 to the first end 39.

The adjustment ring 13, shown by way of example in FIGS. 5 and 6,includes external features 21, internal threads 17, and an annularunder-step 18 forming a groove 19. When assembled, the annularunder-step 18 of adjustment ring 13 engages in the groove 41 of the coreexpanding body 12 and the distal step 26 engages in the groove 19 of theadjustment ring 13, longitudinally fixing the adjustment ring 13 andcore expanding body 12 together while permitting rotational movementtherebetween. External features 21 on the adjustment ring 13 areconfigured to engage a combination inserter/expansion tool which may beoperated to rotate adjustment ring 13 to expand core expanding body 12.The internal threads 17 of the adjustment ring 13 engage with theexternal threads 31 of the inner tubular core 15 so that as theadjustment ring 13 rotates, it acts as a nut and forces the lineartranslation of the inner tubular core 15 along its central axis. Thelongitudinal fixation of the outer tubular core 14 to the adjustmentring 13 ensures the relative displacement of the inner tubular core 15to the outer tubular core 14 as the adjustment ring 13 rotates.

The inner tubular core 15, illustrated in FIG. 9, is composed of a firstend 40 and a generally elongated tubular body 51 extending centrallyfrom the first end 40, and with at least one generally helical exteriorthread 31. The first end 40 of the inner tubular core 15 includesendplate attachment feature 42, as will be discussed in greater detailbelow. One or more guide tracks 19 ingrained into the exterior wall ofthe tubular body 51 run parallel to the central axis of the tubular body51. The guide track 19 receives guide pins 20 which extend through theouter tubular core 14. A guide pin 20 travels along a guide track 19,rotationally fixing inner tubular core 15 to outer tubular core 14,while permitting longitudinal movement therebetween. A guide pin 20 mayhave threaded features that allow it to screw into threaded holes in thewall of the outer tubular core. The threads of the guide pins 20 may besurface treated (e.g. bead blasted) to cause the surface of the threadsto be roughened, which can assist in preventing slippage or back-out ofthe guide pins 20. The rotational fixation between the inner tubularcore 15 to outer tubular core 14 ensure that the inner tubular core 14and outer tubular core 14 (and the vertebrae engaging endplates 11)remain in the desired orientation as the vertebral body implant assembly10 is adjusted, and for the duration that it is implanted in a patient.A central lumen 27 through the inner tubular core 15 enables additionalbone growth promoting material to be placed within the core expandingbody 12, and ultimately to allow new bone to form uninterrupted throughthe entire central axis of the vertebral body implant assembly 10. Thecentral lumen 27 may be generally cylindrical in shape (having agenerally circular cross-section) or in the alternative may have a crosssection having any geometric shape without departing from the scope ofthe present invention.

According to one example embodiment, the vertebral body implant 10 thecore can be made to the following dimensions. The inner and outerdiameter of the tubular body 51 may be generally in the range of 6.1 to13.1 mm and 12.2 to 16.7 mm, respectively. The height of the innertubular core 15 may be generally in the range of 19.4 to 38.9 mm. Theinner and outer diameter of the adjustment ring 13 may be generally inthe range of 10.4 to 15.7 mm and 18.0 to 22.0 mm, respectively. Theheight of the adjustment ring 13 may be generally 7.6 mm. The inner andouter diameter of the outer tubular core 14 may be generally in therange of 11.9 to 16.5 mm and 18.0 to 22.0 mm, respectively. The heightof the outer tubular core 14 may be generally in the range of 14.8 to34.3 mm.

FIGS. 10-12C illustrate in greater detail the features that allow theattachment of the endplates 11 to the expanding tubular core 12. Theendplate 11 includes a first surface 33, a second surface 34, a recessedtubular core attachment feature 35, and at least one window 30 throughthe endplate 11. The windows 30 allow bone growth to form through theendplate 11. The first surface 33 is generally flat, except for therecessed tubular core attachment feature 35. Moreover, although theperimeter of the recessed tubular core attachment feature 35 is shown asrectangular in shape with rounded corners, it will be appreciated thatthe perimeter shape may be provided in any number of suitable shapes ordimensions without departing from the scope of the invention, providedthat the perimeter shape allows the endplate attachment features 42, 22to be received therein. The tubular core attachment feature 35 includesat least one center hole 62 and at least one toothed flange 36 with adistal step feature 37. The toothed flanges 36 are generally the heightof the recess of the tubular core attachment feature 35 and their distalstep feature 37 extends out from the toothed flange 36 in the lateraldirection.

The endplate attachment feature 42 of the inner tubular core 15 ispartially responsible for the secure attachment of an endplate 11 to thefirst end 40 of the inner tubular core 15. The endplate attachmentfeature 42 includes tapered transitions 28 into the central opening 43,and an attachment under-step 29. The central opening 43 allows thecontinuous formation of new bone growth throughout the entire length ofthe inner tubular core 15. The tapered transitions 28 act as guides fortoothed flanges 36 of the endplate 11. As the toothed flanges 36 engagethe tapered transitions 28, the toothed flanges 36 are deflected inward.After the toothed flanges 36 travel the length of a tapered transition28, the toothed flanges 36 return back to their natural positions andengage the attachment under-step 29 (and best viewed in FIG. 12B),locking the endplate 11 to the core expanding body 12.

The perimeter shape of the endplate attachment feature 42 of the innertubular core 15 may be provided in any number of suitable shapes ordimensions without departing from the scope of the invention, providedthat the perimeter shape corresponds to the perimeter shape of thetubular core attachment feature 35 and allows the tubular coreattachment feature 35 to be received therein.

FIG. 12C illustrates the attachment of an endplate 11 to the endplateattachment feature 22 of the outer tubular core 14. The endplateattachment feature 22 is partially responsible for the secure attachmentof an endplate 11. The endplate attachment feature 22 includes taperedtransitions 58 into the central opening 53, and an attachment under-step59. The corresponding features and functions are substantially identicalto those of the endplate attachment feature 42 described previously,such that a repeat discussion is not necessary.

The endplate attachment features 42, 22 allow for the unique ability tocustomize the tubular core expanding body 12 with various endplate 11configurations. The ability to customize the core expanding body 12 mayprovide numerous advantages. By way of example, the customizable coreexpanding body 12 can be used in a variety of surgical approaches (e.g.anterior, anterior-lateral, lateral, etc.). By way of further example,the customizable core expanding body 12 can be placed in a variety ofpositions along the spine, and the customizable core expanding body 12can be made compatible with a variety of conditions of the surroundingvertebral bodies (e.g. partial removal of vertebral body).

The vertebral body implant assembly 10 is preferably composed of eithermetal (e.g. titanium, stainless steel, etc.) or polymer (e.g.poly-ether-ether-ketone (PEEK)). When the implant assembly is made outof a polymer, one or more marker rods 46 are preferably composed of aradiopaque material (e.g. titanium) and are positioned within thevertebral body implant assembly 10 so that the positioning of thevertebral body implant assembly 10 can be visible upon X-ray imaging.This visual indication may be obtained either post-operatively orintra-operatively to confirm placement of the vertebral body implantassembly 10. Additionally, in patients where one or more vertebralbodies have been removed due to diseases, such as tumors, and anvertebral body implant assembly 10 has been implanted between theremaining vertebral bodies, it is beneficial during post-operative x-rayimaging to be able to see through the implant in order to detect anyreoccurrence of the disease.

FIG. 13 illustrates the second surface 34 of the endplate 11 whichincludes one or more liner ridges 60, a taper 61 around the center hole62, an anterior side 64, a posterior side 66, lateral sides 65, and oneor more marker rods 46. When implanted, the second surface 34 isconfigured to be positioned against the adjacent vertebral body with theanterior side 64 positioned generally towards the anterior side of theadjacent vertebral body. The generally larger radii corners at the endsof the anterior side 64 are configured to generally conform to thenatural shape of the anterior portion of a vertebral body. Endplate 11is configured for a preferred use through a lateral approach to thespine, and preferably when endplate coverage is desired to span acrossthe ring apophysis of the vertebra. The distance between the two lateralsides 65 has a length dimensioned to extend generally across the spacefrom the apophyseal ring at one lateral aspect of the spine to theapophyseal ring at the other lateral aspect of the spine. This allowsthe endplate 11 to provide more support and distribute the weight moreevenly throughout the adjacent vertebral body, which lessens stress andpotential damage to the adjacent vertebral body. The ridges 60 provideadditional placement stabilization and are shown in this embodiment tobe generally parallel to the lateral sides 65. The ridges 60 may alsotravel parallel to or in angled directions from the anterior orposterior side 64, 66, without departing from the scope of theinvention. While the ridges 60 are shown as linear, it will beappreciated that the ridges 60 may be non-linear without departing fromthe scope of the present invention. The travel of the ridge 60 isgenerally along the entire length of the lateral side 65, but it mayonly travel a portion of the lateral side 65, or any side, withoutdeparting from the scope of the invention, and therefore is not limitedto the length of travel that the ridge 60 makes along the second surface34 of the endplate 11.

The tapered entry 61 from the second surface 34 into the center hole 62,works like a funnel and provides additional room to impact graftmaterial into the center hole 62 of the endplate 11. At least one markerrod 46 is press fit into the second side 34 of the endplate 11. Theformation of the marker rods 46 are shown by example to be positioned ina rectangular formation, but can be positioned in other configurationswithout departing from the scope of the present invention.

FIG. 14 illustrates another example of an endplate 74 according to analternative embodiment of the present invention. Endplate 74 differsfrom endplate 11 in the perimeter shape. The endplate 74 is generallycircular in shape, and has an outer diameter dimension that is generallyin the range of 22-33 mm. By way of example only, the generally circularendplate 74 is preferred for placement of a vertebral body implantassembly 10 through an anterior approach. Additionally, the generallycircular shape can be beneficial in circumstances where the adjacentvertebral body is more circular in shape.

FIG. 15 illustrates another example of an endplate 84 according to analternative embodiment of the present invention. Endplate 84 differsfrom endplate 74 in the direction of their grooves relative to thegenerally rectangular marker rod 46 formation. The different relativedirections of the grooves cater to different spinal procedures,particularly pertaining to the direction of implant insertion. By way ofexample only, endplate 84 is configured for a preferred use through alateral approach to the spine.

FIG. 16 illustrates another example of an endplate 94 according to analternative embodiment of the present invention. Endplate 94 isconfigured for a preferred use through a lateral surgical approach tothe spine. Endplate 94 has generally the same outer perimeter shape asendplate 11, but in this example the anterior side 95, posterior side98, and lateral sides 96 of endplate 94 are shown to have generallydifferent lengths than the anterior side 64, posterior side 66, andlateral sides 65 of endplate 11. The width of an endplate is defined asthe distance between the anterior side and posterior side of anendplate. Therefore, the width of endplate 11 and endplate 94 ispreferably dimensioned generally in the range of 18-22 mm. The length ofan endplate is defined as the distance between the opposing lateralsides of an endplate. Therefore, the length of endplate 11 and endplate94 is preferably dimensioned generally in the range of 30-60 mm. Thevariable lengths of the sides of endplate 94 and endplate 11 make thecore expanding body 12 even more customizable and enable the vertebralbody implant assembly 10 to maximize the surface area contact betweenthe endplates 11, 94 and the adjacent vertebral body, resulting in theability to provide the most stable support.

FIG. 17 illustrates another example of an endplate 104 according to analternative embodiment of the present invention. The asymmetrical shapeof endplate 104 is configured for a preferred use through a lateralapproach, and generally under the circumstance where a partial removalof the adjacent vertebral body has been performed and endplate coverageis to be biased in one direction relative to the core expanding body 12.Endplate 104 includes an anterior side 105, a posterior side 106, arounded lateral side 107, and a second lateral side 108. The width ofendplate 104 is preferably dimensioned generally in the range of 18-22mm. The length of endplate 104 is preferably dimensioned generally inthe range of 27-40 mm.

FIG. 18 illustrates an example of the angle 97 formed between the firstsurface 33 and second surface 34 of endplate 94. The angle 97 that willbe described for endplate 94 is available in any of the previouslydescribed endplates and is therefore not limited to only endplate 94. Byway of example only, the angle 97 of the endplate 94 is preferablydimensioned generally in the range of 0-15 degrees and functions toimprove the natural curvature of the spine when implanted. The preferreddirection of the angle 97 formed between the first surface 33 and secondsurface 34 lies generally in a plane that is either along or parallel toa ridge 60, which in this example also happens to be parallel to thelateral sides 96. This configuration is intended to accompany specificprocedures and directions that the endplate 94 will be implantedrelative to adjacent vertebral bodies. Additionally, the angle 97 thatis formed between the first surface 33 and second surface 34 may benefitthe maintenance or correction of, for example, either the lordotic orkyphotic curvature of the spine, depending on the direction ofangulation. By way of example only, if the distance between the firstsurface 33 and second surface 34 is greater at the anterior side 95 thanthe posterior side 98 of the endplate 94, then it can be assumed thatthe endplate 94 is configured to have the preferred use to correct ormaintain lordosis. By way of example only, the distance between thefirst surface 33 and second surface 34 of endplate 94 is preferablydimensioned to be generally within the range of 0.4.06-11.81 mm, withthe 11.81 mm dimension being generally the maximum height between thefirst surface 33 and second surface 34 of an endplate configured with a15 degree angle 97. In the condition where the first surface 34 andsecond surface 34 is in a parallel configuration (an angle 97 of zerodegrees), the height between the two surfaces is preferably dimensionedto be generally 4.06 mm.

Although described with respect to specific examples of the differentembodiments, any feature of the endplates disclosed herein by way ofexample only may be applied to any of the embodiments without departingfrom the scope of the present invention. Furthermore, proceduresdescribed, for example only, involving specific regions of the spine(e.g. thoracic and lumbar) may be applied to another region of the spinewithout departing from the scope of the present invention anddimensioning of the implant may be adjusted to accommodate any region.

FIG. 19 illustrates an example embodiment of a vertebral body implantassembly 300 including an additional extension piece 150. Forsimplicity, elements of vertebral body implant assembly 300 that aresubstantially identical to elements of vertebral body implant assembly10 have been assigned the same callout numbers and repeat discussion ofthose elements is excluded. Vertebral body implant assembly 300 may beused, for example, when greater height is required to bridge the spacebetween remaining adjacent vertebral bodies.

FIGS. 20-21 illustrate, by way of example, an extension piece 150. Thefeatures of the extension piece 150 are substantially similar to thefeatures of the outer tubular core 14 described above, including a firstend 39, a second end 41, an endplate attachment feature 22, and aplurality of holes 38. These features are substantially similar (if notidentical) to the corresponding features of the outer tubular core 14,and consequently the details will not be repeated here. Centrallypositioned at the first end 39 of the extension piece 150 is a tubularcore attachment feature 35 which is substantially similar to the tubularcore attachment feature 35 of endplate 11 described above. Thesefeatures are substantially similar (if not identical) to thecorresponding features of the tubular core attachment feature 35 ofendplate 11, and consequently the details will not be repeated here. Theinner and outer diameter of the extension piece 150 is preferablydimensioned to be generally in the range of 11.9 to 16.5 mm and 18.0 to22.0 mm, respectively. The height of the extension piece 150 ispreferably dimensioned to be generally 22.9 mm.

The extension piece 150 can be attached at either end, or both ends, ofthe core expanding body 12. The attachment of the extension piece 150 toeither end of the core expanding body 12 is accomplished using the samefeature orientations described above. For example, the tubular coreattachment feature 35 of the extension piece 150 can become attached tothe endplate attachment feature 22 of the outer tubular core 14 or theendplate attachment feature 42 of the inner tubular core 15. By way ofexample only, the extension piece 150 can be attached to the outertubular core 14 of the core expanding body 12 by aligning them alongtheir center axis and allowing the endplate attachment feature 22 of theouter tubular core 14 to receive the tubular core attachment feature 35of the extension piece 150. This attachment permanently secures theanti-rotational and longitudinal fixation of the extension piece 150 tothe core expanding body 12. When the extension piece 150 is attached toeither end of the core expanding body 12, an endplate 11 (or anyvariation of endplate 11) can be attached to the extension piece 150 byaligning the endplate attachment feature 22 of the extension piece 150with the tubular core attachment feature 35 of endplate 11 and allowingthem to receive each other. This attachment permanently secures theanti-rotational and longitudinal fixation of the endplate 11 to theextension piece 150. Additionally, at least one extension piece 150 canbe attached to at least one extension piece 150 in order to accomplishadditional height of the vertebral body implant assembly 10. Anextension piece 150 can be attached to another extension piece 150 byaligning a tubular core attachment feature 35 of one extension piece 150with an endplate attachment feature 22 of a second extension piece 150and allowing the attachment features 35, 22 to receive each other. Theattachment between a tubular core attachment feature 35 and an endplateattachment feature 22 has been previously described above, and thereforethe details will not be repeated here.

FIGS. 22-31 illustrates an example of an expanding tool 110 for use withthe vertebral body implant assembly 10 described above. By way ofexample only, expanding tool 110 includes a proximal handle 111, amedial handle 112, a distal handle 113, a distal engagement region 114,and an elongated first shaft 115. Distal engagement region 114 includesa plurality of engagement arms 116, a first gear 117, a second gear 118,a third gear 119, and a housing 120 (and best viewed in FIG. 29). By wayof example only, an engagement arm 116 is composed of a base member 121and an extension member 122 connected by a hinge. The engagement arms116, and particularly the extension member 122, are sized anddimensioned to securely grasp the indented slots 23 of the outer tubularcore 14 and secure the position and anti-rotation of the vertebral bodyimplant assembly 10.

The opening (lateral direction) and closing (medial direction) of theengagement arms 116 can be performed by rotating the medial handle 112.The medial handle 112 is fixed to a threaded coupler 170 which hasthreaded features (not shown) in its inside diameter. The threadedfeatures of the coupler 170 are engaged with the threaded features (notshown) on the outside diameter and proximal end 181 of the elongatedsecond shaft 180. At the distal end 182 of the elongated second shaft180, the base member 121 is attached. Therefore, when the medial handle112 is rotated, it causes the threads of the coupler 170 to rotate (andbest viewed in FIG. 28) which forces the second shaft 180 to travellinearly along its central axis and force the proximal hinge members 121to move. By way of example only, movement of a base member 121 forcesthe movement of an extension member 122 in either direction (open orclosed). The direction of travel of the second shaft 180 depends on thedirection of rotation of the medial handle 112 and the direction of thethreaded features. Therefore, by way of example only, a clockwise turnof the medial handle 112 can result in the movement of the engagementarms 116 to an open position due to the advancement of the second shaft180 in the direction of its distal end 182. A set screw 130 (shown inFIG. 22) through the medial handle 112 engages an annular groove 131(best viewed in FIG. 28) at the proximal end 132 of the distal handle113 which allows the medial handle 112 to rotate freely while fixing itslongitudinal position at the proximal end 132 of the distal handle 113.The distal handle 113 is permanently fixed at its distal end 133 to theproximal end 134 of the first shaft 115 which is permanently fixed atits distal end 135 to the housing 120, with both of these connectionspreventing longitudinal and rotational movement relative to each other.The partial function of the distal handle 113 is to provide a graspingarea for the user.

The proximal handle 111 can rotate about its center axis and can do soindependently from the medial handle 112, and vice versa. The end cap165 is secured into the proximal end 140 of the medial handle 112 andone of its functions is to secure the proximal handle 111 to theproximal end 140 of the medial handle 112. Extending rigidly fromapproximately the center of the distal end 142 of the proximal handle111 is the third shaft 144. At the distal end 146 of the third shaft 144is the first gear 117 which can be caused to rotate by rotating theproximal handle 111. An adapter feature 128 at the proximal end 143 ofthe proximal handle 111 enables tools (e.g. t-handles, etc—not shown) tocouple to the adapter feature 128.

A third gear 119 is housed in the superior portion 123 of the housing120 and has third gear features 124 that are compatible with theexternal features 21 of the adjustment ring 13 (and best viewed in FIGS.30-31). This is so that when the expanding tool 110 is fully engagedwith the vertebral body implant assembly 10, the third gear 119 is ableto engage the external features 21 of the adjustment ring 13 and cancause it to rotate. The rotation of the third gear 119 is controlled bythe rotation of the second gear 118 which has second gear features 125that are compatible and engage with the third gear features 124 of thethird gear 119 and cause it to rotate (and best viewed in FIG. 29).Rotation of the second gear 118 is controlled by the rotation of thefirst gear 117, which has first gear features 126 that are compatibleand engage with the second gear features 125 of the second gear 118 andcan cause it to rotate. Rotation of the first gear 117 is accomplishedby rotating the proximal handle 111, as described above.

FIGS. 32 and 33 illustrate one example of a loading block 200, which canbe used for assisting in the attachment of a tubular core attachmentfeature 35 of an endplate to the endplate attachment feature 22, 42 of acore expanding body 12 or extension piece 150. By way of example only,loading block 200 includes a first side 201, a second side 202, a topface 207, and a bottom face 203. Additionally, loading block 200includes endplate profile trenches 205 which consist of a center post204, a base 210, and gutters 206. The endplate profile trenches 205,along with the center posts 204, serve as positioning guides for whenthe endplate is loaded, and for once the endplate is positioned in theloading block 200. By way of example, the center post, which passesthrough the large center hole 62 of the endplate, and the walls of theendplate profile trench 205 both provide a generally sliding fit to thecenter hole 62 and outer profile of the endplate being loaded into theloading block 200. Different dimensions are available for the profilesof the endplate profile trenches 205 and center posts 204 such that eachavailable endplate previously mentioned has a center post 204 andencompassing endplate profile trench 205 that corresponds to its sizeand shape, and, thus, can facilitate in providing secure positioningduring assembly of the endplate. Additionally, the profile shapes of theendplate profile trenches 205 are shaped to accommodate all endplateshapes, both previously mentioned (e.g. rectangular, circular) and arange of variations.

Gutters 206 in the base 210 provide, for example, additional space forany features that may extend from the base of the endplate (e.g. markerrods), allowing the second surface 34 to rest generally flush againstthe base 210. The base 210 of the endplate profile trenches 205 may beflat (parallel to the bottom surface 203 of the loading block 200), ormay be angled so that they can accommodate endplates that have first andsecond surfaces 33, 34 that are angled 97 in relation to each other (forassisting in the correction or maintaining of lordosis). The angles ofthe bases 210 of the loading block 200 are provided in dimensions thatcorrespond to the angles 97 of the first and second surfaces 33, 34 ofthe endplates (as previously discussed) for which the loading block 200is to be used for assembly. A loading block 200 may be provided withmore than one size and shape endplate profile trench 205 and center post204 so that one loading block 200 may be used for the assembly of avariety of endplates. Additionally, more than one base 210 may have adifferent angle within a loading block 200.

Once an endplate is placed completely in the loading block such that thesecond surface 34 of the endplate is generally resting on the base 210with its tubular core attachment feature 35 facing in the direction ofthe top face 207, the endplate is then ready to be assembled to anendplate attachment feature 22, 42. An endplate attachment feature 35 ofeither an inner or outer tubular core 14, 15, or an extension piece 150,is then inserted in the loading block 200 such that its endplateattachment feature 22, 42 is aligned with the tubular core attachmentfeature 35 of the endplate. Once the endplate attachment feature 22, 42is aligned and generally resting on the tubular core attachment feature35, a force can then be applied (for example, by using a mallet of otherinstrument to strike the top of the core expanding body, extensionpiece, or second surface 34 of the endplate that was first attached tothe assembly) to cause the secure attachment of the endplate attachmentfeature 22, 42 to the tubular core attachment feature 35.

In an alternate embodiment, the center post 204 may include an internalthread that travels from the top surface of the center post 204 to atleast a portion of its length. This internal thread could be used toallow a threaded shaft to be secured at one end to the center post 204and still allow the endplate and mating parts to be loaded into theloading block. The opposite end of threaded shaft includes an element toattach and assist in applying the force necessary to cause theattachment of the endplate attachment feature 22, 42 to the tubular coreattachment feature 35. By way of example only, this element couldconsist of a handle and a modified washer such that when the endplateattachment feature 22, 42 was positioned and ready to attach to atubular core attachment feature 35, the modified washer could be placedover the opposite end of the threaded shaft and the handle could bethreaded onto the opposite end of the threaded shaft. The modifiedwasher could act as a protective barrier between the handle and theattachment piece (e.g. inner or outer tubular core) as the handle isscrewed onto the threaded shaft and travels downward (toward the loadingblock). The handle could be screwed onto the end of the threaded shaftand continue to travel downward until it forced the modified washeragainst the attachment piece with enough force to cause the attachmentof the endplate attachment feature 22, 42 to the tubular core attachmentfeature 35.

FIG. 34 illustrates a vertebral body implant assembly 400 according toan additional example embodiment employing alternate mechanisms forcoupling endplates 11 (or any variation described above, e.g. 74, 84,94, 104) with the expanding core body 12, as well as for coupling theexpanding core body 12 and adjustment ring 13 with aninsertion/expansion tool.

FIGS. 35-36 illustrate, by way of example, the end plate 11. Theendplate 11 includes a first surface 33, a second surface 34. The firstsurface 33 is generally flat, and includes recessed tubular coreattachment feature 35. Although the perimeter of the recessed tubularcore attachment feature 35 is shown as rectangular in shape with roundedcorners, it will be appreciated that the perimeter shape may be providedin any number of suitable shapes provided that the perimeter shapeallows the endplate attachment features 42, 22 to be received therein.The tubular core attachment feature 35 includes a center hole 62. Thesecond surface 34 includes a recess 401 including a shoulder 402concentrically adjacent the center hole 62. With endplate attachmentfeatures 22, 42 positioned within the recessed tubular core attachmentfeature 35, an endplate lock screw 404, illustrated by way of example inFIG. 37, cooperates with recessed shoulder 402 to fix the endplates 11to the outer tubular core 14 and the inner tubular core 15.

The endplate lock screw 404 includes a threaded body 406 and a head 410.The threaded body 406 is dimensioned such that it passes through thecenter hole 62 and engages a complementary threaded region 414, 416(FIG. 39) within the endplate attachment features 22, 42 of the outertubular core 14 and inner tubular core 15, respectively. The head 410 isdimensioned such that it fits within the recess 401 and engages shoulder402 when the threaded body 406 is threaded into the endplate attachmentfeatures 42, 22. The lock screw 406 includes a through hole 412extending all the way through the lock screw. Through hole 412communicates with the interior of tubular core 12 to permit bone growthbetween the remaining vertebrae. The sides of through hole 412 areconfigured with an engagement feature 410 to engage a driver tool (notshown) which is utilized to couple the endplate lock screw 404 to thetubular body 12. By way of example, the engagement feature 410 may beconfigured to receive a standard hex wrench. According to one example,the engagement feature 410 (and/or the driver tool) may be tapered tocreate a friction fit between the driver tool and the lock screw 404.The endplate lock screw arrangement of this example embodiment may beadvantageous in that it provides for fast and efficient assembly,disassembly, and reassembly. That is, the implant 10 may be assembledintra-operatively according to a first customized selection (e.g.various endplate sizes and/or shape configurations) and then, as needed,easily disassembled and reassembled according to a second customizedcustomization selection.

With reference again to FIG. 34, the adjustment ring 13 of vertebralbody implant assembly 400 includes engagement features 418 formed alonga beveled side surface 420. By way of example, the side surface may havea 30 degree bevel. The beveled side surface 420 and engagement features418 cooperate with complementary beveled surfaces of a drive wheel 442on expansion instrument 430, described below. Also pictured in FIG. 34,are side receptacles 422 positioned within the indented slots 23 ofouter tubular core 14 and a center receptacles 424 that enhance theconnection between expansion tool 430 and the outer tubular core 14.According to the example shown, center receptacle 424 includes anaperture for receiving set screw 16 to lock the tubular core 12 in thedesired position. While a single set screw 16 is shown, it should beappreciated that multiple set screws 16 may be utilized and the outertubular core 12 may be configured to receive any number of set screws invarious arrangements. For example, the outer tubular body 14 couldinclude apertures on either side of the center receptacle 424 inaddition to, or in place of, the aperture within the center receptaclein order to receive three or two set screws, respectively.

Turning to FIGS. 40-42, there is shown an example embodiment of analternate expansion tool 430 for use with the vertebral replacementimplant 400. Expanding tool 430 includes a grip 431 having a distal grip434 and proximal grip 432, a distal engagement region 438, a drive shaft452, an elongated inner tube 454, and an elongated outer tube 456.Distal engagement region 438 includes a plurality of engagement arms440, a beveled drive wheel 442, and a housing 444. By way of exampleonly, an engagement arm 440 is composed of a base member 446 and anextension member 448 connected by an angled slot 466 and pin 468.Extension arm 448 is also connected to housing 444 by hinge 464. Theengagement arms 440, and particularly the extension member 448, aresized and dimensioned to securely grasp the indented slots 23 of theouter tubular core 14 and secure the position and anti-rotation of thevertebral body implant assembly 400. Ridges 450 on the engagement arms440 complement and engage with the receptacles 422 located in theindented slots to provide additional stabilization.

The opening (lateral direction) and closing (medial direction) of theengagement arms 440 can be performed by squeezing the grip 431. Theproximal grip 432 is fixed to the inner tube 454 by a joint 458 throughan opening 460 in the outer tube 456. The distal end of the inner tube454 meanwhile is fixed to the base members 446 of the engagement arms.The outer tube 456 is fixed at one end to the distal handle 434. At theopposite end the outer tube 456 is fixed to the housing 444. Thus,squeezing the grip 431 causes the proximal handle 432 to translate theinner tube 454 toward the distal end moving the base member 446distally, which in turn causes the extension arms 448 to rotate aroundthe hinge 464 as the pin 468 moves through angled slot 466. With theengagement arms 440 coupled to the implant 400, a locking mechanism maybe engaged to prevent decoupling of the implant. By way of example, thelocking mechanism may include a ratchet arm 470 attached to one of theproximal and distal grips. Additionally, or in place of the ratchet arm470, the locking mechanism may include a threaded nut 472 attached to anarm 474 attached to one of the proximal and distal grips and extendingthrough an opening in the opposite grip.

The drive shaft 452 traverses through the inner tube 454 and is fixed tothe beveled drive wheel 442 within housing 44. Rotating the drive shaft452 causes the beveled drive wheel to rotate in the same direction.Thus, when the expansion tool 430 is fixedly coupled to the implant 400and the drive shaft 452 is rotated, the drive wheel will impart rotationto the adjustment ring 13, causing expansion of the tubular body 12.

FIG. 43A-43E illustrates one example of a preferred use of a vertebralbody implant assembly 10 coupled with an expanding tool 110. While FIGS.43A-43E picture implant 10 and expanding tool 110, it should beappreciated that the implant 400 and expanding tool 430 may be usedaccording to the same principals while substituting the differencesdescribed above. FIG. 43A shows an anterior view of a portion of aspine, which includes a superior vertebra, a medial vertebra and aninferior vertebra which are shown labeled as V1, V2, and V3respectively. In FIG. 43B, the medial vertebra has been removed so thatthere is now a large space between the superior and inferior vertebralbodies. In the following figure, FIG. 43C, endplates 11 have been chosenthat are preferred for being positioned against the surfaces of thesuperior and inferior vertebral bodies. These selected endplates 11 areshown being attached (without the use of a loading block 200) at theendplate attachment features 22, 42 of the inner tubular core 15 andouter tubular core 14 of the core expanding body 12. As previouslymentioned, a loading block 200 may be used to assist in attaching theendplates to the endplate attachment features 22, 42. The expanding tool110 can then grasp the indented slots 23 of the outer tubular core 14 byturning the proximal handle 111. This is accomplished by turning theproximal handle 111 one way so that the engagement arms 116 can open andreceive the vertebral body implant assembly 10 between the engagementarms 116. Once the core expanding body 12 is positioned between theengagement arms 116, the proximal handle 111 is turned in the oppositedirection so that the engagement arms 116 securely grasp the vertebralbody implant assembly 10, and preferably so that the engagement arms 116grasp the vertebral body implant assembly 10 at the general location ofthe indented slots 23 on the outer tubular core 14.

By way of example only, FIG. 43D illustrates the vertebral body implantassembly 10 being inserted in its collapsed state from a lateraldirection into the space remaining between the superior and inferiorvertebral bodies using the expanding tool 110. The height of thevertebral body implant assembly 10 is then increased by rotating themedial handle 112 which causes the third gear 119 to rotate, asdescribed above. Since the vertebral body implant assembly 10 is securedbetween the engagement arms 116, the third gear 119 of the expandingtool 110 can engage the external features 21 of the adjustment ring 13so that when the third gear 119 rotates, it causes the adjustment ring13 to rotate in concert. As detailed above, rotation of the adjustmentring 13 causes expansion of the vertebral body implant assembly 10, asshown in FIG. 43E. The vertebral body implant assembly 10 is expandeduntil its desired height has been achieved. It is also possible torotate the proximal handle 111 in the opposite direction in order tocause the vertebral body implant assembly 10 to decrease in height. Oncethe desired height has been achieved, the medial handle 112 is rotatedin the direction to cause the engagement arms 116 to open and releasethe vertebral body implant assembly 10. The expanding tool 110 is thenseparated from the vertebral body implant assembly 10 so that at leastone set screw 16 from the outer tubular core 14 can be engaged into theouter wall of the inner tubular core 15 in order to secure the expandedheight of the vertebral body implant assembly 10. Additional bone growthpromoting material can then be added to the vertebral body implantassembly 10 before it is left to remain implanted between the first andsecond vertebrae.

While not specifically described above, it will be understood thatvarious other steps may be performed in using and implanting the devicesdisclosed herein, including but not limited to creating an incision in apatient's skin, distracting and retracting tissue to establish anoperative corridor to the surgical target site, advancing the implantthrough the operative corridor to the surgical target site, removinginstrumentation from the operative corridor upon insertion of theimplant, and closing the surgical wound.

While this invention has been described in terms of a best mode forachieving this invention's objectives, it will be appreciated by thoseskilled in the art that variations may be accomplished in view of theseteachings without deviating from the spirit or scope of the invention.

What is claimed is:
 1. A method for implanting a vertebral body implantfrom a lateral direction into a space remaining between a first vertebraand a second vertebra of a spine after removal of at least part of onevertebra, the method comprising: selecting first and second endplatesfrom a plurality of differently sized endplates for attachment to anintermediate expansion member, the first and second plates beingconfigured to engage the first and second vertebrae through a lateralapproach to the spine after the removal of said at least part of onevertebra; after selecting the first and second endplates, assembling thefirst endplate to the intermediate expansion member via a firstmechanical structure of the first endplate that mates with a firstcomplementary mechanical structure at a first end of the intermediateexpansion member, the intermediate expansion member having an axis andan axial length extending between the first end and a second end,wherein the intermediate expansion member includes a ring memberrotatable about the axis of the intermediate expansion member to adjustthe axial length between the first end and the second end from acollapsed state to an expanded state, wherein the first endplateincludes: a central aperture generally aligned with the axis of theintermediate expansion member and spaced inwardly from an anterior side,a posterior side, and opposing lateral sides of the first endplate, aplate width of 18 mm to 22 mm extending between opposing flat regions ofthe anterior side and the posterior side which extend generally parallelto one another, a plate length of 30 mm to 60 mm extending generallybetween the opposing lateral sides and being perpendicular to the platewidth; after selecting the first and second endplates, assembling thesecond endplate to the intermediate expansion member via a secondmechanical structure of the second endplate that mates with a secondcomplementary mechanical structure at the second end of the intermediateexpansion member, wherein the second endplate includes: a centralaperture generally aligned with the axis of the intermediate expansionmember and spaced inwardly from an anterior side, a posterior side, andopposing lateral sides of the second endplate, a plate width of 18 mm to22 mm extending between opposing flat regions of the anterior side andthe posterior side which extend generally parallel to one another, aplate length of 30 mm to 60 mm extending generally between the opposinglateral sides and being perpendicular to the plate width; releasablymounting an inserter tool to a pair of indented slots of theintermediate expansion member, the indented slots being symmetricallyoffset on opposing sides of a central longitudinal plane of theintermediate expansion member, the central longitudinal plane passingthrough the axis of the intermediate expansion member and beinggenerally parallel to the plate length of each of the first and secondendplates, the inserter tool including a gear that engages the ringmember of the intermediate expansion member; while the inserter tool isreleasably mounted to the intermediate expansion member and the firstand second endplates assembled to the intermediate expansion member,laterally inserting the intermediate expansion member in the collapsedstate from a lateral direction into the space remaining between thefirst and second vertebrae; and after laterally inserting theintermediate expansion member into the space, rotating the gear of theinserter tool about an axis that is generally parallel to the axis ofthe intermediate expansion member so as to rotate the ring member aboutthe axis of the intermediate expansion member, wherein the rotation ofthe ring member of the intermediate expansion member causes theintermediate expansion member to adjust from the collapsed state to theexpanded state so that anti-migration features of the first endplatesecure to the first vertebra and anti-migration features of the secondendplate secure to the second vertebra.
 2. The method of claim 1,further comprising inserting bone growth promoting material to aninterior space of the intermediate expansion member after laterallyinserting the intermediate expansion member into the space and aftercausing the intermediate expansion member to adjust from the collapsedstate to the expanded state.
 3. The method of claim 2, wherein saidinserting bone growth promoting material to the interior space of theintermediate expansion member comprises inserting the bone growthpromoting material through an elongate opening formed in a sidewall ofthe intermediate expansion member, wherein the central longitudinalplane extending between the pair of indented slots bisects the elongateopening, the elongate opening having an aperture height extendinggenerally parallel to the axis of the intermediate expansion member andan aperture width extending generally perpendicularly to the apertureheight, the aperture height being greater than the aperture width. 4.The method of claim 2, wherein the interior space of the intermediateexpansion member is in communication with the central aperture of firstendplate and the central aperture of second endplate.
 5. The method ofclaim 1, further comprising engaging a set screw into the intermediateexpansion member so as to lock the intermediate expansion member in theexpanded state.
 6. The method of claim 1, wherein the intermediateexpansion member includes said rotatable ring member, an outer coremember, an inner core member configured to linearly translate in anaxial direction relative to the outer core member in response torotation of said rotatable ring member relative to said outer coremember.
 7. The method of claim 6, wherein said rotatable ring member isrotatable relative to the outer core member while being generally fixedin said axial direction relative to the outer core member, said innercore member being non-rotatable relative to the outer core member whilebeing configured to linearly translate in the axial direction relativeto the outer core member, wherein said rotatable ring member comprisesan internal thread configured to mate with an exterior thread of theinner core member, and external engagement structures extending radiallyoutwardly for mating with a tool, and wherein at least a portion of theinner core member that engages with the outer core member is positionedradially inward of the outer core member, and at least a portion of theouter core member that engages with the rotatable ring member ispositioned radially inward of the rotatable ring member.
 8. The methodof claim 1, wherein the first endplate is defined by a perimeter thatincludes anterior and posterior aspects that extend longitudinallystraight and generally parallel to the plate length of the first plateand opposing lateral aspects including convexly curved portions.
 9. Themethod of claim 1, wherein said selecting the first and second endplatesfrom the plurality of differently sized endplates comprises: selectingthe first endplate of a size to extend across the space from anapophyseal ring at a first lateral aspect of the first vertebra to theapophyseal ring at a second opposing lateral aspect of the firstvertebra, and selecting the first endplate of a size to extend acrossthe space from an apophyseal ring at a first lateral aspect of thesecond vertebra to the apophyseal ring at a second opposing lateralaspect of the second vertebra.
 10. The method of claim 1, wherein afterlaterally inserting the intermediate expansion member into the space,the plate length the first endplate extends across the space from anapophyseal ring at a first lateral aspect of the first vertebra to theapophyseal ring at a second opposing lateral aspect of the firstvertebra, and the plate length the second endplate extends across thespace from an apophyseal ring at a first lateral aspect of the secondvertebra to the apophyseal ring at a second opposing lateral aspect ofthe second vertebra.
 11. The method of claim 1, wherein the plate widthof the first and second endplates is 22 mm, and the plate length of thefirst and second endplates is 30 mm to 60 mm.
 12. A method forimplanting a vertebral body implant from a lateral direction into aspace remaining between a first vertebra and a second vertebra afterremoval of at least part of one vertebra, the method comprising:selecting first and second lateral insertion endplates from a pluralityof differently sized endplates and attaching the selected first andsecond lateral insertion endplates to opposing ends of an intermediateexpansion member, wherein each of the first and second lateral insertionendplates includes: a central aperture generally aligned with an axis ofthe intermediate expansion member and spaced inwardly from an anteriorside, a posterior side, and opposing lateral sides of the respectiveendplate, a plate width of 18 mm to 22 mm extending between opposingflat regions of the anterior side and the posterior side which extendgenerally parallel to one another, a plate length of 30 mm to 60 mmextending generally between the opposing lateral sides and beingperpendicular to the plate width; releasably mounting an inserter toolto the intermediate expansion member so that a longitudinal axis of theinserter tool extends generally parallel to the plate length of each ofthe first and second endplates, the inserter tool including a gear thatengages the intermediate expansion member and that is rotatable about agear axis generally perpendicular to the longitudinal axis of theinserter tool; while the inserter tool is releasably mounted to theintermediate expansion member and the first and second endplatesassembled to the intermediate expansion member, laterally inserting theintermediate expansion member in a collapsed state from a lateraldirection into the space remaining between the first and secondvertebrae; and after laterally inserting the intermediate expansionmember into the space, rotating the gear of the inserter tool to causethe intermediate expansion member to adjust from the collapsed state toan expanded state.
 13. The method of claim 12, further comprisinginserting bone growth promoting material to an interior space of theintermediate expansion member after laterally inserting the intermediateexpansion member into the space and after causing the intermediateexpansion member to adjust from the collapsed state to the expandedstate.
 14. The method of claim 13, wherein said inserting bone growthpromoting material to the interior space of the intermediate expansionmember comprises inserting the bone growth promoting material through anelongate opening formed in a sidewall of the intermediate expansionmember, wherein the central longitudinal plane extending between thepair of indented slots bisects the elongate opening, the elongateopening having an aperture height extending generally parallel to theaxis of the intermediate expansion member and an aperture widthextending generally perpendicularly to the aperture height, the apertureheight being greater than the aperture width.
 15. The method of claim13, wherein the interior space of the intermediate expansion member isin communication with the central aperture of first endplate and thecentral aperture of second endplate.
 16. The method of claim 12, furthercomprising engaging a set screw into the intermediate expansion memberso as to lock the intermediate expansion member in the expanded state.17. The method of claim 12, wherein the intermediate expansion memberhas an axis and an axial length extending between the opposing ends,wherein the intermediate expansion member includes: a ring memberrotatable about the axis of the intermediate expansion member to adjustthe axial length between the opposing ends from the collapsed state tothe expanded state, an outer core member, an inner core memberconfigured to linearly translate in an axial direction relative to theouter core member in response to rotation of said rotatable ring memberrelative to said outer core member.
 18. The method of claim 17, whereinsaid rotatable ring member is rotatable relative to the outer coremember while being generally fixed in said axial direction relative tothe outer core member, said inner core member being non-rotatablerelative to the outer core member while being configured to linearlytranslate in the axial direction relative to the outer core member,wherein said rotatable ring member comprises an internal threadconfigured to mate with an exterior thread of the inner core member, andexternal engagement structures extending radially outwardly for matingwith a tool, and wherein at least a portion of the inner core memberthat engages with the outer core member is positioned radially inward ofthe outer core member, and at least a portion of the outer core memberthat engages with the rotatable ring member is positioned radiallyinward of the rotatable ring member.
 19. The method of claim 12, whereinthe first endplate is defined by a perimeter that includes anterior andposterior aspects that extend longitudinally straight and generallyparallel to the plate length of the first plate and opposing lateralaspects including convexly curved portions.
 20. The method of claim 12,wherein said selecting the first and second endplates from the pluralityof differently sized endplates comprises: selecting the first endplateof a size to extend across the space from an apophyseal ring at a firstlateral aspect of the first vertebra to the apophyseal ring at a secondopposing lateral aspect of the first vertebra, and selecting the firstendplate of a size to extend across the space from an apophyseal ring ata first lateral aspect of the second vertebra to the apophyseal ring ata second opposing lateral aspect of the second vertebra.
 21. The methodof claim 12, wherein after laterally inserting the intermediateexpansion member into the space, the plate length the first endplateextends across the space from an apophyseal ring at a first lateralaspect of the first vertebra to the apophyseal ring at a second opposinglateral aspect of the first vertebra, and the plate length the secondendplate extends across the space from an apophyseal ring at a firstlateral aspect of the second vertebra to the apophyseal ring at a secondopposing lateral aspect of the second vertebra.